The present invention relates to a miter saw, and more particularly, to such a miter saw capable of performing angled cutting in which a side surface of the circular saw blade extends obliquely relative to a fence and capable of performing slant cutting in which the side surface extends obliquely relative to a base section.
In a conventional table top circular saw, a workpiece such as a wood block is mounted on a base section, and the workpiece is cut by a circular saw unit vertically movable above the base section. If the workpiece is to be cut obliquely, a posture of the workpiece on the base section must be changed. Thus, workability may be lowered.
Japanese Patent Application Publication No. 2000-254817 discloses a miter saw including a base section, a support section, and a circular saw unit. The base section includes a base and a turntable mounted on the base and rotatable about its axis. A workpiece is mounted on the turntable. The support section upwardly extends from the turntable and is laterally tiltable. The circular saw unit is positioned above the base section and is pivotally movably supported to the support section. The circular saw unit includes a circular saw blade and a motor for rotating the blade.
For the angled cutting, the turntable is angularly rotated about its axis to change the angle of the side surface of the circular saw blade relative to a fence. For the slant cutting, the support section is tiltingly moved relative to the turntable and is fixed at a desired tilted posture. Thus, the circular saw unit is slanted relative to the upper surface of the turntable.
In order to perform angled cutting a scale engraved at the turntable is used, and in order to perform slant cutting a scale engraved at the circular saw unit is used. However, error may be involved due to visual recognition to the scales for reading the angularly moving angle and the tilting angle. To avoid this problem, a digital display is required for displaying these angles.
For the digital display, rotation angle of the turntable and tilting angle of the circular saw unit must be provisionally detected, and the detected data must be converted into digital signal. The signal must be stored in a RAM so as to compute the rotation angle and the tilting angle in a microcomputer. The computed angles are then displayed on the digital display.
However, the computation in the microcomputer and the storage in the RAM cannot be performed if an electrical power source is disconnected. Accordingly, if the turntable is angularly rotated and then the electrical power source is turned ON, displayed angle is incorrect. In the latter case, angle setting adjustment must be performed.